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Nervous - Eternity Vasquez period 6 - Coggle Diagram
Nervous - Eternity Vasquez period 6
Basal Nuclei
( Ganglia)
Functions: Influence muscle movements, play role in cognition and emotion, regulate intensity of slow or stereotyped movements, filter out incorrect/ inappropriate responses, inhibit antagonists/unnecessary movements
Disorders: Parkinson's and Huntington's Disease
Traumatic Brain Injuries
Concussion: temporary alternation in function
Contussion: permanent damage
Subdural or subarachnoid hemorrage: pressure from blood may force brain stem through foramen magnum, results in death
Cerebral edema: swelling of brain associated with traumatic head injury
Degenerative Brain Disorders
Alzheimer's Disease
: dementia, memory loss, short attention span, moodiness, irritability, confusion
Parkinson's Disease:
degeneration of dopamine, cause mitochondrial abnormalities or protein
Hunington's Disease:
caused by accumulation, leads to degeneration of basal nuclei and cerebral cortex, fatal within 15 years of onset
Gross Anatomy and Protection
SPINAL CORD: functions: provides 2 way communication to and from brain and body. Major reflex center, reflexes are initiated and completed at spinal cord
EPIDURAL SPACE: cushion of fat and network of veins in space between vertebrae and spinal dura matter
Filum Terminate: extension of conuscovered with pia mater, anchors spinal cord
Denticulate Ligaments: extension of pia mater that secure cord to dura matter
cervical (controls upper limbs) and lumbar ( controls lower limbs) enlargements are areas where nerves servicing upper and lower limbs arise from spinal cord
Spinal Nerves: Part of PNS, attach to spinal cord by 31 paired roots
formed by fusion of dorsal and ventral roots
Central Nervous System
Consists of brain and spinal cord
* Brain Regions
Cerebral Hemispheres
Surface Markings: Gyri: ridges / Sulci: Shallow Grooves / Fissures: deep grooves /
Longitudinal Fissure: Separates two hemispheres
Transverse Cerebral Fissure: Separates Cerebellum and cerebrum
Function: Responsible for communication between cerebral hemispheres and between CNS
Classified according to direction they run:
association, commissural, projection fibers
Brain Stem
Midbrain
Cerebral Aqueduct: channel running thru midbrain that connects third & fourth ventricle
Pons
4th ventricle separates pons and cerebellum, located between midbrain and medulla
Medulla
Contains fourth ventricle / contains choroid plexus: capillary rich membrane that forms cerebral spinal fluid
Cardiovascular center: cardiac center adjusts force and rate of heart contraction, vasomotor cortex adjusts blood vessel diameter for blood pressure regulation
Diencephalon
- Thalamus
: function: relay station for information coming into cortex, acts to mediate sensation, motor activities, cortical arousal, learning, and memory
- Hypothalamus :
location: under the thalamus. Function: forms brain stem and inferolateral walls of third ventricle, regulates body temp, hunger and satiety in response to nutrient blood levels or hormones, water balance and thirst, sleep wake cycles
hyothalamus contains nuclei like: Mammillary Bodies= act as olfactory relay stations
infundibulum: connects to pituitary gland
Epithalamus: location: dorsal portion of diencephalon. Functions: Forms roof of third ventricle. Contains pineal glan (body): - extends from posterior border, - secretes melatonin that helps regulate sleep wake cycle
Cerebellum
Function: - Processes input from cortex, brain stem, and sensory receptors to provide precise / plays role in thinking, language, and emotion / balance and coordination
Location: dorsal to pons and medulla
Limbic System
Fornix: large part of emotional or affective brain
Puts emotional responses to orders
Most output relayed via hypothalamus
Language
Broca's Area: Involved in speech productions
Wernicke's area: understanding spoken and written words
Meninges
Functions:
Cover and protect CNS
Protect blood vessels and enclose venous sinuses
contains CSF
Form partitions in skull
3 types of layers
Dura Mater: Strongest Meninx
Arachnoid Mater: middle layer; separated by the subdural space
Subarachnoid space: contains CSF and largest blood vessels of brain
Pia Mater: delicate CT that clings tightly to brain following very convolution
Cerebrovascular Accidents
(referred to as "strokes")
Ischemia : Tissue deprived of blood supply, leads to death of brain tissue
Hemiplegia: (paralysis on one side) or sensory and speech defits may result
Transient Ischemic Attacks: temporary episodes of reversible cerebral ischemia
Tissue plasminogen Activator: only approved treatment for stroke
Diagnostic Procedure for CNS Dysfunction
Knee jerk reflex with hammer tapped against quadriceps tendon
CT, MRI, PET <- allow for quick identification of tumors, lesions, plaque
Cerebral Angiography: uses X rays with dye to pinpoint ny stroke causing clots
Ultrasounds: evaluate blood flow through arteries feeding the brain
Gray Matter and Spinal Roots
dorsal horns: receive somatic and visceral sensory input
ventral horns: somatic motor neurons
lateral horns: only in thoracic and superior lumbar regions
Gray commissure: bridge of gray matter that connects masses of gray matter on either side, encloses central cord
ventral roots: motor neuron axons that exit the spinal cord
dorsal roots: sensory input to cord
Gray matter divided into 4 groups (based on somatic or visceral innervation)
Somatic Sensory, Visceral Sensory, Visceral Motor, and Somatic Motor
White Matter
Myelinated and Nonmyelinated nerve fibers allow communication between parts of spinal cord and spinal cord & brain
Divided into three directions: Ascending, Descending, and Transverse
Divided into three white columns on each side: Dorsal (posterior), Lateral, Ventral (anterior)
Spinal Cord Traumas and Disorders:
Paresthesias: damage to dorsal roots or sensory tracts/ leads to sensory function loss
Paralysis: damage to ventral roots or ventral horn cells/ leads to motor function loss
two types: spastic and flaccid
Neuronal Pathways
Decussation: Pathways cross from one side of cns to another
Relay: consists of chain of two or three neurons
Somatotopy: precise spatial relationship in cns correspond to spatial relationship in body
Symmetry: Pathways are paired symmetrically ( right and left )
Nervous System
Function: master controlling and communicating system of body
3 overlapping functions:
Sensory Input: info gathered by sensory receptors about internal and external changes (INFO COMING IN)
Integration: Processing and interpretation of sensory input (WHERE IT GOES AND WHAT IT NEEDS TO DO)
Motor Output: activation of effector organs produce a response (ACTION)
Central Nervous System
brain and spinal cord of dorsal body cavity
Integration and control center: interprets sensory input and dictates motor output
Peripheral Nervous System
Consists mainly of nerves that extend from brain and spinal cord:
Spinal Nerves: to and from spinal cord
Cranial Nerves: to and from brain
Functional Divisions of Peripheral
Sensory division: (towards)
somatic sensory fibers: conveys impulses from skin, skeletal muscles and joints to CNS
Visceral sensory fibers: convey impulses from visceral organs to CNS
Motor division: (away)
transmit impulses from CNS to effector organs
Neuroglia
(of cells)
Two cell types:
Neuroglia (glial cells): small cells that surround and wrap delicate neurons
Neurons (nerve cells): excitable cells that transmit electrical signals
Neuroglia of CNS
Astrocytes
Functions:
support and brace neurons
Play role in exchanges between capillaries and neurons
guide migration of young neurons
-control chemical environment around neurons
respond to nerve impulses and neurotransmitters
influence neuronal functioning
info processing in brain
Microglial Cells
gets rid of harmful things
Ependymal Cells
Range in shape from squamous to columnar
may be ciliated
line the central cavities of the brain
form permeable and tissue fluid bathing cns cells
Oligodendrocytes
Produces myelin in cns
processes wrap cns nerve fibers, forming insulated myelin sheaths ( cushion; increase nerve conduction ) in thicker nerve fibers
Neuroglia of PNS
Two major neuroglia seen in PNS
Satellite cells
surround neuron
function similar as astrocytes of cns
schwann cells
surround all peripheral nerve fibers and form myelin sheaths in thicker nerve fibers
Neuron Processes
Tracts: bundles of neuron processes in cns
Nerves: bundles of neuron processes in pns
dendrites: toward
axon: away
Classification of neurons
Structural
Multipolar
Bipolar
Unipolar
Functional
Sensory
Motor
Interneurons
Operation of Gated Channels
Chemically gated ion channels: open in response to binding of the appropriate neurotransmitter
Voltage gated ion channels: open in response to changes in membrane potentials
Changing Resting Membrane Potential
Graded potential: incoming signals operating over short distances
Action potential: Long distance signals of axons
Depolarization:decrease in membrane potential
Hyperpolarization: increase in membrane potential
Generating on Action Potential
Resting State: All gated Na^+ and K^+ channels are closed
Depolarization: Na^+ channels open
Repolarization:Na^+ are inactivating, K^+ open
Hyperpolarization: Some K^+ stay open, Na^+ reset
Info transfer across Chemical Synapse
AP arrives at axon terminal of presynaptic neuron
Voltage gated Ca^2+ open, Ca^2+ enters axon terminal
Ca^2+ entry= synaptic vesicles release neurotransmitter
Neurotransmitter diffuses across synaptic cleft, binds to receptor on the postsynaptic membrane
Bind neurotransmitter opens ion channels creating graded potentials
Neurotransmitter effectors are terminated
Classify Neurotransmitter by Chemical Structure
Acetylcholine: released at neuromuscular junction
Biogenic Amines
Amino Acids: makes up all proteins = difficult to prove which are neurotransmitters
Peptides: strings of amino acids that diverse functions
Purines: monomers of nucleic acids have effect in cns and pns
Patterns of Neural Processing
Serial Processing: input travels along one pathway to specific destination
Reflexes: 5 components= Receptors, Sensory Neuron, CNS integration center, motor neuron, and effector
Parallel Processing: input travels along several pathways
Sensory Receptors:
respond to changes in environment
3 ways they are classified: type of stimulus, body location, structural complexity
Classify of Stimulus Type
Mechanoreceptors: respond to touch, pressure, vibration, and stretch
Photoreceptors: respond to light energy
Thermoreceptors: sensitive to changes in temp
Chemoreceptors: respond to chemicals
Nociceptors: sensitive to pain causing stimulus
Classify by Location
Exteroceptors: respond to stimuli arising outside body, receptors in skin for touch,pressure, pain, temperature
Interoceptors: respond to stimuli in internal viscera and blood vessels, sensitive to chemical changes, tissue stretch, and temp changes
Proprioceptors: respond to stretch in skeletal muscles, tendons, joints, ligaments, and ct coverings of bones and muscles, inform brain of one's movement
Perception of Pain
Pain Tolerance
Perceive pain at same stimulus intensity
sensitive to pain = low tolerance pain, NOT low pain threshold
Genes also determine pain tolerance
Visceral Pain
results from stimulation of visceral organ receptors
felt as vague aching, gnawing, burning
activated by tissue, stretching, ischemia, chemicals, muscles spasms
Referred Pain
pain from one body region perceived as coming from different region
viscera and somatic pain fibers travel along some nerves, brain assumes stimulus
Sensory Processing
Survival depends upon:
Sensation: awareness of changing in internal and external environment
Perception: conscious interpretation of those stimuli
Organization of the Somato Sensory System
-Somatosensory System: receives input from= Exteroceptors, Proprioceptors, Interoceptors
Levels of neural integration in sensory system:
Receptor Level: sensory receptors
Circuit Level: Process in ascending pathways
Perceptual Level: press in cortical sensory area
Transmission Lines: Nerves and their structure and repair
Nerve: cordlike organ of PNS
2 types of nerves: Spinal or Cranial
CT coverings include:
endoneurium: loose CT encloses axons and their myelin sheaths (Schwann cells)
perineurium: coarse CT bundle fibers into fascicles
epineurium: tough fibrous sheath around all fascicles to form the nerve
Mixed nerves: contain sensory and motor fibers
Sensory (afferent) nerves: toward CNS
Motor (efferent) nerves: away from CNS
Regeneration of Nerve Fibers
CNS Axons
fibers NEVER regenerate
astrocytes at injury site form scar tissue
treatments: neutralizing growth inhibitors, blocking receptors for inhibitory proteins , destroying scar tissue components
PNS Axons
CAN regenerate
axon fragments and myelin sheaths distal to injury degenerate: degeneration slows down axon
Macrophages clean dead axon debris
axon filaments grow through regeneration tube
axon regenerates and new myelin sheath forms
Overview of Cranial Nerves
Olfactory Nerves : (smell)
Optic Nerves: (Vision)
3 Oculomotor nerves: (eye movements)
Trochlear Nerves: (eye movement)
Trigemial Nerves: ( chewing and sensory to face)
Abducens nerves: ( eye movement)
Facial Nerves: (actual facial expression)
Vestibulocochlear Nerves: ( hearing)
Glossopharyngeal Nerves: (taste, swallowing)
Vagus Nerves: ( gag reflex)
Accessory Nerves ( goes to neck, purely motor)
Hypoglossal Nerves (swallowin)
Spinal Nerves
Ventral Roots
Has motor fibers from ventral horn motor neurons that innervate skeletal muscles
Dorsal Roots
has sensory fibers from sensory neurons in dorsal root ganglia that conduct impulses from peripheral receptors